Communication system incorporated in an ingestible product

ABSTRACT

The system of the present invention includes a conductive element, an electronic component, and a partial power source in the form of dissimilar materials. Upon contact with a conducting fluid, a voltage potential is created and the power source is completed, which activates the system. The electronic component controls the conductance between the dissimilar materials to produce a unique current signature. The system can also be associated with food and communicate data about ingestion of food material to a receiver.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/180,507, filed on Jul. 11, 2011, entitled COMMUNICATION SYSTEMINCORPORATED IN AN INGESTIBLE PRODUCT, now U.S. Pat. No. 8,836,513,which is related to U.S. patent application Ser. No. 12/564,017, filedon Sep. 21, 2009 and entitled COMMUNICATION SYSTEM WITH PARTIAL POWERSOURCE, now U.S. Pat. No. 7,978,064, which is a continuation-in-partapplication of U.S. patent application Ser. No. 11/912,475 filed Jun.23, 2008 and entitled PHARMA-INFORMATICS SYSTEM, now U.S. Pat. No.8,847,766 which application is a 371 application of PCT Application No.PCT/US06/16370 filed Apr. 28, 2006 and entitled PHARMA-INFORMATICSSYSTEM; which application pursuant to 35 U.S.C. §119(e), claims priorityto the filing dates of: U.S. Provisional Patent Application Ser. No.60/676,145 filed Apr. 28, 2005 and entitled PHARMA-INFORMATICS SYSTEM;U.S. Provisional Patent Application Ser. No. 60/694,078 filed Jun. 24,2005 and entitled PHARMA-INFORMATICS SYSTEM; U.S. Provisional PatentApplication Ser. No. 60/713,680 filed Sep. 1, 2005 and entitled MEDICALDIAGNOSTIC AND TREATMENT PLATFORM USING NEAR-FIELD WIRELESSCOMMUNICATION OF INFORMATION WITHIN A PATIENT′S BODY; and U.S.Provisional Patent Application Ser. No. 60/790,335 filed Apr. 7, 2006and entitled PHARMA-INFORMATICS SYSTEM; the disclosures of which areherein incorporated by reference.

This application is also related to the following U.S. Applications, thedisclosures of which are incorporated herein by reference: U.S.application Ser. No. 13/180,516, entitled COMMUNICATION SYSTEM WITHREMOTE ACTIVATION, now U.S Patent Application Publication No.2012-0007734A1 ; U.S. application Ser. No. 13/180,498, entitledCOMMUNICATION SYSTEM WITH MULTIPLE SOURCES OF POWER, now U.S. PatentApplication Publication No. 2012-0004520A1 ; U.S. application Ser. No.13/180,539, entitled COMMUNICATION SYSTEM USING AN IMPLANTABLE DEVICE,now U.S. Pat. No. 8,730,031; U.S. application Ser. No. 13/180,525,entitled COMMUNICATION SYSTEM WITH ENHANCED PARTIAL POWER SOURCE ANDMETHOD OF MANUFACTURING SAME, now U.S. Pat. No. 8,802,183; and U.S.application Ser. No. 13/180,538 entitled POLYPHARMACY CO-PACKAGEDMEDICATION DOSING UNIT INCLUDING COMMUNICATION SYSTEM THEREFOR, now U.S.Patent Application Publication No. 2012-0024889A1.

FIELD

The present invention is related to communication systems for detectionof an event. More specifically, the present disclosure includes a systemthat includes a device for association with ingestible ingredients orproducts.

INTRODUCTION

Ingestible devices that include electronic circuitry have been proposedfor use in a variety of different medical applications, including bothdiagnostic and therapeutic applications. These devices typically requirean internal power supply for operation. Examples of such ingestibledevices are ingestible electronic capsules which collect data as theypass through the body, and transmit the data to an external receiversystem. An example of this type of electronic capsule is an in-vivovideo camera. The swallowable capsule includes a camera system and anoptical system for imaging an area of interest onto the camera system.The transmitter transmits the video output of the camera system and thereception system receives the transmitted video output. Other examplesinclude an ingestible imaging device, which has an internal andself-contained power source, which obtains images from within bodylumens or cavities. The electronic circuit components of the device areenclosed by an inert indigestible housing (e.g. glass housing) thatpasses through the body internally. Other examples include an ingestibledata recorder capsule medical device. The electronic circuits of thedisclosed device (e.g. sensor, recorder, battery etc.) are housed in acapsule made of inert materials.

In other examples, fragile radio frequency identification (RFID) tagsare used in drug ingestion monitoring applications. In order for theRFID tags to be operational, each requires an internal power supply. TheRFID tags are antenna structures that are configured to transmit aradio-frequency signal through the body.

The problem these existing devices pose is that the power source isinternal to device and such power sources are costly to produce andpotentially harmful to the surrounding environment if the power sourceleaks or is damaged. Additionally, having antennas extending from thedevice is a concern as related to the antennas getting damaged orcausing a problem when the device is used in-vivo. Therefore, what isneeded is suitable system with circuitry that eliminates the need for aninternal power source and antennas.

SUMMARY

The present disclosure includes a system for producing a uniquesignature that indicates the occurrence of an event. The system includescircuitry and components that can be placed within certain environmentsthat include a conducting fluid. One example of such an environment isinside a container that houses the conducting fluid, such as a sealedbag with a solution, which includes an IV bag. Another example is withinthe body of a living organism, such as an animal or a human. The systemsare ingestible and/or digestible or partially digestible. The systemincludes dissimilar materials positioned on the framework such that whena conducting fluid comes into contact with the dissimilar materials, avoltage potential difference is created. The voltage potentialdifference, and hence the voltage, is used to power up control logicthat is positioned within the framework. Ions or current flows from thefirst dissimilar material to the second dissimilar material via thecontrol logic and then through the conducting fluid to complete acircuit. The control logic controls the conductance between the twodissimilar materials and, hence, controls or modulates the conductance.

As the ingestible circuitry is made up of ingestible, and evendigestible, components, the ingestible circuitry results in little, ifany, unwanted side effects, even when employed in chronic situations.Examples of the range of components that may be included are: logicand/or memory elements; effectors; a signal transmission element; and apassive element, such as a resistor or inductor. The one or morecomponents on the surface of the support may be laid out in anyconvenient configuration. Where two or more components are present onthe surface of the solid support, interconnects may be provided. All ofthe components and the support of the ingestible circuitry areingestible, and in certain instances digestible or partially digestible.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows an event indicator system in communication with animplanted device in according to the teaching of the present invention.

FIG. 2A shows the pharmaceutical product of FIG. 1 with the eventindicator system on the exterior of the pharmaceutical product.

FIG. 2B shows the pharmaceutical product of FIG. 1 with the eventindicator system positioned inside the pharmaceutical product.

FIG. 3 is a block diagram representation of one aspect of the eventindicator system with dissimilar metals positioned on opposite ends.

FIG. 4 is a block diagram representation of another aspect of the eventindicator system with dissimilar metals positioned on the same end andseparated by a non-conducting material.

FIG. 5 shows ionic transfer or the current path through a conductingfluid when the event indicator system of FIG. 3 is in contact withconducting liquid and in an active state.

FIG. 5A shows an exploded view of the surface of dissimilar materials ofFIG. 5.

FIG. 5B shows the event indicator system of FIG. 5 with a pH sensorunit.

FIG. 6 is a block diagram illustration of one aspect of the controldevice used in the system of FIGS. 3 and 4.

DETAILED DESCRIPTION

The present disclosure includes multiple aspects for indicating theoccurrence of an event. As described in more detail below, a system ofthe present invention is used with a conducting fluid to indicate theevent marked by contact between the conducting fluid and the system. Forexample, the system of the present disclosure may be used withpharmaceutical product and the event that is indicated is when theproduct is taken or ingested. The term “ingested” or “ingest” or“ingesting” is understood to mean any introduction of the systeminternal to the body. For example, ingesting includes simply placing thesystem in the mouth all the way to the descending colon. Thus, the termingesting refers to any instant in time when the system is introduced toan environment that contains a conducting fluid. Another example wouldbe a situation when a non-conducting fluid is mixed with a conductingfluid. In such a situation the system would be present in thenon-conduction fluid and when the two fluids are mixed, the system comesinto contact with the conducting fluid and the system is activated. Yetanother example would be the situation when the presence of certainconducting fluids needed to be detected. In such instances, the presenceof the system, which would be activated, within the conducting fluidcould be detected and, hence, the presence of the respective fluid wouldbe detected.

Referring again to the instance where the system is used with theproduct that is ingested by the living organism, when the product thatincludes the system is taken or ingested, the device comes into contactwith the conducting liquid of the body. When the system of the presentinvention comes into contact with the body fluid, a voltage potential iscreated and the system is activated. A portion of the power source isprovided by the device, while another portion of the power source isprovided by the conducting fluid, which is discussed in detail below.

Referring now to FIG. 1, an ingestible capsule 14 that includes a systemof the present invention is shown inside the body. The capsule 14 isconfigured as an orally ingestible pharmaceutical formulation in theform of a pill or capsule. Upon ingestion, the capsule 14 moves to thestomach. Upon reaching the stomach, the capsule 14 is in contact withstomach fluid 18 and undergoes a chemical reaction with the variousmaterials in the stomach fluid 18, such as hydrochloric acid and otherdigestive agents. The system of the present invention is discussed inreference to a pharmaceutical environment. However, the scope of thepresent invention is not limited thereby. The present invention can beused in any environment where a conducting fluid is present or becomespresent through mixing of two or more components that result in aconducting liquid.

Referring now to FIG. 2A, a pharmaceutical product 10, similar to thecapsule 14 of FIG. 1, is shown with a system 12, such as an ingestibleevent marker or an ionic emission module. The scope of the presentinvention is not limited by the shape or type of the product 10. Forexample, it will be clear to one skilled in the art that the product 10can be a capsule, a time-release oral dosage, a tablet, a gel cap, asub-lingual tablet, or any oral dosage product that can be combined withthe system 12.

Additionally, the system 12 of the present invention may be ingestedwithout a pharmaceutical product via a carrier capsule that includesonly the system with no other active agent. In accordance with anotheraspect of the present invention, the system 12 may be used as part of afood product or an ingredient in a food product. For example, the system12 is coated with a protective material as discussed in detail below.The system 12 is then included is the food product similar to anyingredient. Thus, ingestion of that food product may be trackedautomatically, which is often useful in setting where knowing the exactfood take and time of ingestion is needed, for example when a person hasa special diet or is receiving care at a hospital as a patient orin-patient.

In accordance with another example of the present invention, the system12 may be combined with an ingredient commonly used in making food. Forexample, the system 12 may be secured to salt in a manner similar to theway the system 12 is secured to a pharmaceutical product, as discussedbelow. Then as the ingredient with the system 12 is mixed into the food,the food will include the system which will become activated uponingestion.

In accordance with various aspects of the present invention, when thesystem 12 is combined with food and ingested there are variousapproaches to activation of the system 12. In accordance with one aspectof the present invention, the system 12 may be coated with a materialthat breaks and releases the system 12 as the food is being masticated,e.g. chewed or squashed. In accordance with another aspect of thepresent invention, the coating material may be reactive to saliva andwhen in contact with saliva will dissolve or disintegrate and releasethe system 12. Conducting fluids associated with saliva may activate thesystem 12. In accordance with yet another aspect of the presentinvention, the coating material may be reactive to stomach acids anddissolve or disintegrate upon contact with the stomach fluids to releasethe system 12. In accordance with another aspect of the presentinvention, the coating material may be made of material that resistsbreaking or dissolving when masticated or exposed to saliva, such as thebeads found in drinks. In accordance with another aspect of the presentinvention, the coating material may be intentionally destroyed or brokenapart when distributed or mixed in with a food, such as when bread ismixed and prepared for a food (e.g. pizza dough).

Continuing with FIG. 2A, in the shown aspect, the product 10 has thesystem 12 secured to the exterior using known methods of securingmicro-devices to the exterior of pharmaceutical products or aningestible ingredient, for example food or ingredients of food. Exampleof methods for securing the micro-device to the product is disclosed inU.S. Provisional Application No. 61/142,849 filed on Jan. 1, 2009 andentitled “HIGH-THROUGHPUT PRODUCTION OF INGESTIBLE EVENT MARKERS” aswell as U.S. Provisional Application No. 61/177,611 filed on May 12,2009 and entitled “INGESTIBLE EVENT MARKERS COMPRISING AN IDENTIFIER ANDAN INGESTIBLE COMPONENT”, the entire disclosure of each is incorporatedherein by reference. Once ingested, the system 12 comes into contactwith body liquids and the system 12 is activated. The system 12 uses thevoltage potential difference to power up and thereafter modulatesconductance to create a unique and identifiable current signature. Uponactivation, the system 12 controls the conductance and, hence, currentflow to produce the current signature.

There are various reasons for delaying the activation of the system 12.In order to delay the activation of the system 12, the system 12 may becoated with a shielding material or protective layer. The layer isdissolved over a period of time, thereby allowing the system 12 to beactivated when the product 10 has reached a target location.

Referring now to FIG. 2B, a pharmaceutical product or an ingestibleproduct/ingredient 20, similar to the capsule 14 of FIG. 1, is shownwith a system 22, such as an ingestible event marker or an identifiableemission module. The scope of the present invention is not limited bythe environment to which the system 22 is introduced. For example, thesystem 22 can be enclosed in a capsule that is taken in additionto/independently from the pharmaceutical product or ingestibleingredient. The capsule may be simply a carrier for the system 22 andmay not contain any product. Furthermore, the scope of the presentinvention is not limited by the shape or type of product 20. Forexample, it will be clear to one skilled in the art that the product 20can be a food product or ingredient, a capsule, a time-release oraldosage, a tablet, a gel capsule, a sub-lingual tablet, or any oraldosage product. In the referenced aspect, the product 20 has the system22 positioned inside or secured to the interior of the product 20. Inone aspect, the system 22 is secured to the interior wall of the product20. When the system 22 is positioned inside a gel capsule, then thecontent of the gel capsule is a non-conducting gel-liquid. On the otherhand, if the content of the gel capsule is a conducting gel-liquid, thenin an alternative aspect, the system 22 is coated with a protectivecover to prevent unwanted activation by the gel capsule content. If thecontent of the capsule is a dry powder or microspheres, then the system22 is positioned or placed within the capsule. If the product 20 is atablet or hard pill, then the system 22 is held in place inside thetablet. Once ingested, the product 20 containing the system 22 isdissolved. The system 22 comes into contact with body liquids and thesystem 22 is activated. Depending on the product 20, the system 22 maybe positioned in either a near-central or near-perimeter positiondepending on the desired activation delay between the time of initialingestion and activation of the system 22. For example, a centralposition for the system 22 means that it will take longer for the system22 to be in contact with the conducting liquid and, hence, it will takelonger for the system 22 to be activated. Therefore, it will take longerfor the occurrence of the event to be detected.

Referring now to FIG. 3, in one aspect, the systems 12 and 22 of FIGS.2A and 2B, respectively, are shown in more detail as system 30. Thesystem 30 can be used in association with any pharmaceutical product, asmentioned above, to determine when a patient takes the pharmaceuticalproduct. As indicated above, the scope of the present invention is notlimited by the environment and the product that is used with the system30. For example, the system 30 may be placed within a capsule and thecapsule is placed within the conducting liquid. The capsule would thendissolve over a period of time and release the system 30 into theconducting liquid. Thus, in one aspect, the capsule would contain thesystem 30 and no product. Such a capsule may then be used in anyenvironment where a conducting liquid is present and with any product.For example, the capsule may be dropped into a container filled with jetfuel, salt water, tomato sauce, motor oil, or any similar product.Additionally, the capsule containing the system 30 may be ingested atthe same time that any pharmaceutical product is ingested in order torecord the occurrence of the event, such as when the product was taken.

In the specific example of the system 30 combined with thepharmaceutical product, as the product or pill is ingested, the system30 is activated. The system 30 controls conductance to produce a uniquecurrent signature that is detected, thereby signifying that thepharmaceutical product has been taken. The system 30 includes aframework 32. The framework 32 is a chassis for the system 30 andmultiple components are attached to, deposited upon, or secured to theframework 32. In this aspect of the system 30, a digestible material 34is physically associated with the framework 32. The material 34 may bechemically deposited on, evaporated onto, secured to, or built-up on theframework all of which may be referred to herein as “deposit” withrespect to the framework 32. The material 34 is deposited on one side ofthe framework 32. The materials of interest that can be used as material34 include, but are not limited to: Cu or CuI. The material 34 isdeposited by physical vapor deposition, electrodeposition, or plasmadeposition, among other protocols. The material 34 may be from about0.05 to about 500 μm thick, such as from about 5 to about 100 μm thick.The shape is controlled by shadow mask deposition, or photolithographyand etching. Additionally, even though only one region is shown fordepositing the material, each system 30 may contain two or moreelectrically unique regions where the material 34 may be deposited, asdesired.

At a different side, which is the opposite side as shown in FIG. 3,another digestible material 36 is deposited, such that materials 34 and36 are dissimilar. Although not shown, the different side selected maybe the side next to the side selected for the material 34. The scope ofthe present invention is not limited by the side selected and the term“different side” can mean any of the multiple sides that are differentfrom the first selected side. Furthermore, even though the shape of thesystem is shown as a square, the shape maybe any geometrically suitableshape. Material 34 and 36 are selected such that they produce a voltagepotential difference when the system 30 is in contact with conductingliquid, such as body fluids. The materials of interest for material 36include, but are not limited to: Mg, Zn, or other electronegativemetals. As indicated above with respect to the material 34, the material36 may be chemically deposited on, evaporated onto, secured to, orbuilt-up on the framework. Also, an adhesion layer may be necessary tohelp the material 36 (as well as material 34 when needed) to adhere tothe framework 32. Typical adhesion layers for the material 36 are Ti,TiW, Cr or similar material. Anode material and the adhesion layer maybe deposited by physical vapor deposition, electrodeposition or plasmadeposition. The material 36 may be from about 0.05 to about 500 μmthick, such as from about 5 to about 100 μm thick. However, the scope ofthe present invention is not limited by the thickness of any of thematerials nor by the type of process used to deposit or secure thematerials to the framework 32.

According to the disclosure set forth, the materials 34 and 36 can beany pair of materials with different electrochemical potentials.Additionally, in the aspects wherein the system 30 is used in-vivo, thematerials 34 and 36 may be vitamins that can be absorbed. Morespecifically, the materials 34 and 36 can be made of any two materialsappropriate for the environment in which the system 30 will beoperating. For example, when used with an ingestible product, thematerials 34 and 36 are any pair of materials with differentelectrochemical potentials that are ingestible. An illustrative exampleincludes the instance when the system 30 is in contact with an ionicsolution, such as stomach acids. Suitable materials are not restrictedto metals, and in certain aspects the paired materials are chosen frommetals and non-metals, e.g., a pair made up of a metal (such as Mg) anda salt (such as CuCl or CuI). With respect to the active electrodematerials, any pairing of substances—metals, salts, or intercalationcompounds—with suitably different electrochemical potentials (voltage)and low interfacial resistance are suitable.

Materials and pairings of interest include, but are not limited to,those reported in Table 1 below. In one aspect, one or both of themetals may be doped with a non-metal, e.g., to enhance the voltagepotential created between the materials as they come into contact with aconducting liquid. Non-metals that may be used as doping agents incertain aspects include, but are not limited to: sulfur, iodine and thelike. In another aspect, the materials are copper iodine (CuI) as theanode and magnesium (Mg) as the cathode. Aspects of the presentinvention use electrode materials that are not harmful to the humanbody.

TABLE 1 Anode Cathode Metals Magnesium, Zinc Sodium , Lithium Iron SaltsCopper salts: iodide, chloride, bromide, sulfate, formate, (other anionspossible) Fe³⁺ salts: e.g. orthophosphate, pyrophosphate, (other anionspossible) Oxygen or Hydrogen ion (H+) on platinum, gold or othercatalytic surfaces Intercalation Graphite with Li, Vanadium oxidecompounds K, Ca, Na, Mg Manganese oxide

Thus, when the system 30 is in contact with the conducting liquid, acurrent path, an example is shown in FIG. 5, is formed through theconducting liquid between material 34 and 36. A control device 38 issecured to the framework 32 and electrically coupled to the materials 34and 36. The control device 38 includes electronic circuitry, for examplecontrol logic that is capable of controlling and altering theconductance between the materials 34 and 36.

The voltage potential created between the materials 34 and 36 providesthe power for operating the system as well as produces the current flowthrough the conducting fluid and the system. In one aspect, the systemoperates in direct current mode. In an alternative aspect, the systemcontrols the direction of the current so that the direction of currentis reversed in a cyclic manner, similar to alternating current. As thesystem reaches the conducting fluid or the electrolyte, where the fluidor electrolyte component is provided by a physiological fluid, e.g.,stomach acid, the path for current flow between the materials 34 and 36is completed external to the system 30; the current path through thesystem 30 is controlled by the control device 38. Completion of thecurrent path allows for the current to flow and in turn a receiver, notshown, can detect the presence of the current and recognize that thesystem 30 has been activate and the desired event is occurring or hasoccurred.

In one aspect, the two materials 34 and 36 are similar in function tothe two electrodes needed for a direct current power source, such as abattery. The conducting liquid acts as the electrolyte needed tocomplete the power source. The completed power source described isdefined by the electrochemical reaction between the materials 34 and 36of the system 30 and enabled by the fluids of the body. The completedpower source may be viewed as a power source that exploitselectrochemical conduction in an ionic or a conducting solution such asgastric fluid, blood, or other bodily fluids and some tissues.

Additionally, the environment may be something other than a body and theliquid may be any conducting liquid. For example, the conducting fluidmay be salt water or a metallic based paint.

In certain aspects, these two materials are shielded from thesurrounding environment by an additional layer of material. Accordingly,when the shield is dissolved and the two dissimilar materials areexposed to the target site, a voltage potential is generated.

In certain aspects, the complete power source or supply is one that ismade up of active electrode materials, electrolytes, and inactivematerials, such as current collectors, packaging, etc. The activematerials are any pair of materials with different electrochemicalpotentials. Suitable materials are not restricted to metals, and incertain aspects the paired materials are chosen from metals andnon-metals, e.g., a pair made up of a metal (such as Mg) and a salt(such as CuI). With respect to the active electrode materials, anypairing of substances—metals, salts, or intercalation compounds—withsuitably different electrochemical potentials (voltage) and lowinterfacial resistance are suitable.

A variety of different materials may be employed as the materials thatform the electrodes. In certain aspects, electrode materials are chosento provide for a voltage upon contact with the target physiologicalsite, e.g., the stomach, sufficient to drive the system of theidentifier. In certain aspects, the voltage provided by the electrodematerials upon contact of the metals of the power source with the targetphysiological site is 0.001 V or higher, including 0.01 V or higher,such as 0.1 V or higher, e.g., 0.3 V or higher, including 0.5 volts orhigher, and including 1.0 volts or higher, where in certain aspects, thevoltage ranges from about 0.001 to about 10 volts, such as from about0.01 to about 10 V.

Referring again to FIG. 3, the materials 34 and 36 provide the voltagepotential to activate the control device 38. Once the control device 38is activated or powered up, the control device 38 can alter conductancebetween the materials 34 and 36 in a unique manner. By altering theconductance between materials 34 and 36, the control device 38 iscapable of controlling the magnitude of the current through theconducting liquid that surrounds the system 30. This produces a uniquecurrent signature that can be detected and measured by a receiver (notshown), which can be positioned internal or external to the body. Inaddition to controlling the magnitude of the current path between thematerials, non-conducting materials, membrane, or “skirt” are used toincrease the “length” of the current path and, hence, act to boost theconductance path, as disclosed in the U.S. patent application Ser. No.12/238,345 entitled, “In-Body Device with Virtual Dipole SignalAmplification” filed Sep. 25, 2008, the entire content of which isincorporated herein by reference. Alternatively, throughout thedisclosure herein, the terms “non-conducting material”, “membrane”, and“skirt” are interchangeably with the term “current path extender”without impacting the scope or the present aspects and the claimsherein. The skirt, shown in portion at 35 and 37, respectively, may beassociated with, e.g., secured to, the framework 32. Various shapes andconfigurations for the skirt are contemplated as within the scope of thepresent invention. For example, the system 30 may be surrounded entirelyor partially by the skirt and the skirt maybe positioned along a centralaxis of the system 30 or off-center relative to a central axis. Thus,the scope of the present invention as claimed herein is not limited bythe shape or size of the skirt. Furthermore, in other aspects, thematerials 34 and 36 may be separated by one skirt that is positioned inany defined region between the materials 34 and 36.

Referring now to FIG. 4, in another aspect, the systems 12 and 22 ofFIGS. 2A and 2B, respectively, are shown in more detail as system 40.The system 40 includes a framework 42. The framework 42 is similar tothe framework 32 of FIG. 3. In this aspect of the system 40, adigestible or dissolvable material 44 is deposited on a portion of oneside of the framework 42. At a different portion of the same side of theframework 42, another digestible material 46 is deposited, such thatmaterials 44 and 46 are dissimilar. More specifically, material 44 and46 are selected such that they form a voltage potential difference whenin contact with a conducting liquid, such as body fluids. Thus, when thesystem 40 is in contact with and/or partially in contact with theconducting liquid, then a current path, an example is shown in FIG. 5,is formed through the conducting liquid between material 44 and 46. Acontrol device 48 is secured to the framework 42 and electricallycoupled to the materials 44 and 46. The control device 48 includeselectronic circuitry that is capable of controlling part of theconductance path between the materials 44 and 46. The materials 44 and46 are separated by a non-conducting skirt 49. Various examples of theskirt 49 are disclosed in U.S. Provisional Application No. 61/173,511filed on Apr. 28, 2009 and entitled “HIGHLY RELIABLE INGESTIBLE EVENTMARKERS AND METHODS OF USING SAME” and U.S. Provisional Application No.61/173,564 filed on Apr. 28, 2009 and entitled “INGESTIBLE EVENT MARKERSHAVING SIGNAL AMPLIFIERS THAT COMPRISE AN ACTIVE AGENT”; as well as U.S.application Ser. No. 12/238,345 filed Sep. 25, 2008 and entitled“IN-BODY DEVICE WITH VIRTUAL DIPOLE SIGNAL AMPLIFICATION”; the entiredisclosure of each is incorporated herein by reference.

Once the control device 48 is activated or powered up, the controldevice 48 can alter conductance between the materials 44 and 46. Thus,the control device 48 is capable of controlling the magnitude of thecurrent through the conducting liquid that surrounds the system 40. Asindicated above with respect to system 30, a unique current signaturethat is associated with the system 40 can be detected by a receiver (notshown) to mark the activation of the system 40. In order to increase the“length” of the current path the size of the skirt 49 is altered. Thelonger the current path, the easier it may be for the receiver to detectthe current.

Referring now to FIG. 5, the system 30 of FIG. 3 is shown in anactivated state and in contact with conducting liquid. The system 30 isgrounded through ground contact 52. For example, when the system 30 isin contact with a conducting fluid, the conducting fluid provides theground. The system 30 also includes a sensor module 74, which isdescribed in greater detail with respect to FIG. 6. Ion or current paths50 between material 34 to material 36 and through the conducting fluidin contact with the system 30. The voltage potential created between thematerial 34 and 36 is created through chemical reactions betweenmaterials 34/36 and the conducting fluid.

The system 30 also includes a unit 75. The unit 75 includescommunication functions and in accordance with the various aspects ofthe present invention can act as any of the following: a receiver, atransmitter, or a transceiver. Thus, another device that is external tothe system 30, such as a cell phone, an implanted device, a deviceattached to the user's body, or a device placed under the user's skincan communicate with the system 30 through the unit 75. The unit 75 isalso electrically connected to the materials 34 and 36. In accordancewith one aspect of the present invention, any device that is external tothe system 30 may communicate with either the unit 75 or the controlmodule 38 using current flow through the environment surrounding thesystem 30. For example, a patch or receiver that is attached to theuser's body, a cell phone or device being held by the user, or animplanted device, any of which can generate a current signature throughthe user's body. The current signature can include information that isencoded therein. The current signature is detected by the system 30,using the unit 75 or the control module 38, and decoded to allowcommunication to the system 30 from the device external to system 30.Accordingly, the external device can send a signal to the unit 75,either wirelessly or through transconduction, that controls theactivation of the system 30.

If the conditions of the environment change to become favorable tocommunication, as determined by the measurements of the environment,then the unit 75 sends a signal to the control device 38 to alter theconductance between the materials 34 and 36 to allow for communicationusing the current signature of the system 30. Thus, if the system 30 hasbeen deactivated and the impedance of the environment is suitable forcommunication, then the system 30 can be activated again.

Referring now to FIG. 5A, this shows an exploded view of the surface ofthe material 34. In one aspect, the surface of the material 34 is notplanar, but rather an irregular surface. The irregular surface increasesthe surface area of the material and, hence, the area that comes incontact with the conducting fluid. In one aspect, at the surface of thematerial 34, there is an electrochemical reaction between the material34 and the surrounding conducting fluid such that mass is exchanged withthe conducting fluid. The term “mass” as used here includes any ionic ornon-ionic species that may be added or removed from the conductive fluidas part of the electrochemical reactions occurring on material 34. Oneexample includes the instant where the material is CuCl and when incontact with the conducting fluid, CuCl is converted to Cu metal (solid)and Cl— is released into the solution. The flow of positive ions intothe conducting fluid is depicted by the current path 50. Negative ionsflow in the opposite direction. In a similar manner, there is anelectrochemical reaction involving the material 36 that results in ionsreleased or removed from the conducting fluid. In this example, therelease of negative ions at the material 34 and release of positive ionsby the material 36 are related to each other through the current flowthat is controlled by the control device 38. The rate of reaction andhence the ionic emission rate or current, is controlled by the controldevice 38. The control device 38 can increase or decrease the rate ofion flow by altering its internal conductance, which alters theimpedance, and therefore the current flow and reaction rates at thematerials 34 and 36. Through controlling the reaction rates, the system30 can encode information in the ionic flow. Thus, the system 30 encodesinformation using ionic emission or flow.

The control device 38 can vary the duration of ionic flow or currentwhile keeping the current or ionic flow magnitude near constant, similarto when the frequency is modulated and the amplitude is constant. Also,the control device 38 can vary the level of the ionic flow rate or themagnitude of the current flow while keeping the duration near constant.Thus, using various combinations of changes in duration and altering therate or magnitude, the control device 38 encodes information in thecurrent or the ionic flow. For example, the control device 38 may use,but is not limited to any of the following techniques, including BinaryPhase-Shift Keying (PSK), Frequency modulation, Amplitude modulation,on-off keying, and PSK with on-off keying.

As indicated above, the various aspects disclosed herein, such assystems 30 and 40 of FIGS. 3 and 4, respectively, include electroniccomponents as part of the control device 38 or the control device 48.Components that may be present include but are not limited to: logicand/or memory elements, an integrated circuit, an inductor, a resistor,and sensors for measuring various parameters. Each component may besecured to the framework and/or to another component. The components onthe surface of the support may be laid out in any convenientconfiguration. Where two or more components are present on the surfaceof the solid support, interconnects may be provided.

As indicated above, the system, such as control devices 30 and 40,control the conductance between the dissimilar materials and, hence, therate of ionic flow or current. Through altering the conductance in aspecific manner the system is capable of encoding information in theionic flow and the current signature. The ionic flow or the currentsignature is used to uniquely identify the specific system.Additionally, the systems 30 and 40 are capable of producing variousdifferent unique patterns or signatures and, thus, provide additionalinformation. For example, a second current signature based on a secondconductance alteration pattern may be used to provide additionalinformation, which information may be related to the physicalenvironment. To further illustrate, a first current signature may be avery low current state that maintains an oscillator on the chip and asecond current signature may be a current state at least a factor of tenhigher than the current state associated with the first currentsignature.

Referring now to FIG. 6, a block diagram representation of the controldevice 38 is shown. The control device 30 includes a control module 62,a counter or clock 64, and a memory 66. Additionally, the device 38 isshown to include a sensor module 72 as well as the sensor module 74,which was referenced in FIG. 5. The control module 62 has an input 68electrically coupled to the material 34 and an output 70 electricallycoupled to the material 36. The control module 62, the clock 64, thememory 66, and the sensor modules 72/74 also have power inputs (some notshown). The power for each of these components is supplied by thevoltage potential produced by the chemical reaction between materials 34and 36 and the conducting fluid, when the system 30 is in contact withthe conducting fluid. The control module 62 controls the conductancethrough logic that alters the overall impedance of the system 30. Thecontrol module 62 is electrically coupled to the clock 64. The clock 64provides a clock cycle to the control module 62. Based upon theprogrammed characteristics of the control module 62, when a set numberof clock cycles have passed, the control module 62 alters theconductance characteristics between materials 34 and 36. This cycle isrepeated and thereby the control device 38 produces a unique currentsignature characteristic. The control module 62 is also electricallycoupled to the memory 66. Both the clock 64 and the memory 66 arepowered by the voltage potential created between the materials 34 and36.

The control module 62 is also electrically coupled to and incommunication with the sensor modules 72 and 74. In the aspect shown,the sensor module 72 is part of the control device 38 and the sensormodule 74 is a separate component. In alternative aspects, either one ofthe sensor modules 72 and 74 can be used without the other and the scopeof the present invention is not limited by the structural or functionallocation of the sensor modules 72 or 74. Additionally, any component ofthe system 30 may be functionally or structurally moved, combined, orrepositioned without limiting the scope of the present invention asclaimed. Thus, it is possible to have one single structure, for examplea processor, which is designed to perform the functions of all of thefollowing modules: the control module 62, the clock 64, the memory 66,and the sensor module 72 or 74. On the other hand, it is also within thescope of the present invention to have each of these functionalcomponents located in independent structures that are linkedelectrically and able to communicate.

Referring again to FIG. 6, the sensor modules 72 or 74 can include anyof the following sensors: temperature, pressure, pH level, andconductivity. In one aspect, the sensor modules 72 or 74 gatherinformation from the environment and communicate the analog informationto the control module 62. The control module then converts the analoginformation to digital information and the digital information isencoded in the current flow or the rate of the transfer of mass thatproduces the ionic flow. In another aspect, the sensor modules 72 or 74gather information from the environment and convert the analoginformation to digital information and then communicate the digitalinformation to control module 62. In the aspect shown in FIG. 5, thesensor modules 74 is shown as being electrically coupled to the material34 and 36 as well as the control device 38. In another aspect, as shownin FIG. 6, the sensor module 74 is electrically coupled to the controldevice 38 at connection 78. The connection 78 acts as both a source forpower supply to the sensor module 74 and a communication channel betweenthe sensor module 74 and the control device 38.

Referring now to FIG. 5B, the system 30 includes a pH sensor module 76connected to a material 39, which is selected in accordance with thespecific type of sensing function being performed. The pH sensor module76 is also connected to the control device 38. The material 39 iselectrically isolated from the material 34 by a non-conductive barrier55. In one aspect, the material 39 is platinum. In operation, the pHsensor module 76 uses the voltage potential difference between thematerials 34/36. The pH sensor module 76 measures the voltage potentialdifference between the material 34 and the material 39 and records thatvalue for later comparison. The pH sensor module 76 also measures thevoltage potential difference between the material 39 and the material 36and records that value for later comparison. The pH sensor module 76calculates the pH level of the surrounding environment using the voltagepotential values. The pH sensor module 76 provides that information tothe control device 38. The control device 38 varies the rate of thetransfer of mass that produces the ionic transfer and the current flowto encode the information relevant to the pH level in the ionictransfer, which can be detected by a receiver (not shown). Thus, thesystem 30 can determine and provide the information related to the pHlevel to a source external to the environment.

As indicated above, the control device 38 can be programmed in advanceto output a pre-defined current signature. In another aspect, the systemcan include a receiver system that can receive programming informationwhen the system is activated. In another aspect, not shown, the switch64 and the memory 66 can be combined into one device.

In addition to the above components, the system 30 may also include oneor other electronic components. Electrical components of interestinclude, but are not limited to: additional logic and/or memoryelements, e.g., in the form of an integrated circuit; a power regulationdevice, e.g., battery, fuel cell or capacitor; a sensor, a stimulator,etc.; a signal transmission element, e.g., in the form of an antenna,electrode, coil, etc.; a passive element, e.g., an inductor, resistor,etc.

In certain aspects, the ingestible circuitry includes a coating layer.The purpose of this coating layer can vary, e.g., to protect thecircuitry, the chip and/or the battery, or any components duringprocessing, during storage, or even during ingestion. In such instances,a coating on top of the circuitry may be included. Also of interest arecoatings that are designed to protect the ingestible circuitry duringstorage, but dissolve immediately during use. For example, coatings thatdissolve upon contact with an aqueous fluid, e.g. stomach fluid, or theconducting fluid as referenced above. Also of interest are protectiveprocessing coatings that are employed to allow the use of processingsteps that would otherwise damage certain components of the device. Forexample, in aspects where a chip with dissimilar material deposited onthe top and bottom is produced, the product needs to be diced. However,the dicing process can scratch off the dissimilar material, and alsothere might be liquid involved which would cause the dissimilarmaterials to discharge or dissolve. In such instances, a protectivecoating on the materials prevents mechanical or liquid contact with thecomponent during processing can be employed. Another purpose of thedissolvable coatings may be to delay activation of the device. Forexample, the coating that sits on the dissimilar material and takes acertain period of time, e.g., five minutes, to dissolve upon contactwith stomach fluid may be employed. The coating can also be anenvironmentally sensitive coating, e.g., a temperature or pH sensitivecoating, or other chemically sensitive coating that provides fordissolution in a controlled fashion and allows one to activate thedevice when desired. Coatings that survive the stomach but dissolve inthe intestine are also of interest, e.g., where one desires to delayactivation until the device leaves the stomach. An example of such acoating is a polymer that is insoluble at low pH, but becomes soluble ata higher pH. Also of interest are pharmaceutical formulation protectivecoatings, e.g., a gel cap liquid protective coating that prevents thecircuit from being activated by liquid of the gel cap.

Identifiers of interest include two dissimilar electrochemicalmaterials, which act similar to the electrodes (e.g., anode and cathode)of a power source. The reference to an electrode or anode or cathode areused here merely as illustrative examples. The scope of the presentinvention is not limited by the label used and includes the aspectwherein the voltage potential is created between two dissimilarmaterials. Thus, when reference is made to an electrode, anode, orcathode it is intended as a reference to a voltage potential createdbetween two dissimilar materials.

When the materials are exposed and come into contact with the bodyfluid, such as stomach acid or other types of fluid (either alone or incombination with a dried conductive medium precursor), a potentialdifference, that is, a voltage, is generated between the electrodes as aresult of the respective oxidation and reduction reactions incurred tothe two electrode materials. A voltaic cell, or battery, can thereby beproduced. Accordingly, in aspects of the invention, such power suppliesare configured such that when the two dissimilar materials are exposedto the target site, e.g., the stomach, the digestive tract, etc., avoltage is generated.

In certain aspects, one or both of the metals may be doped with anon-metal, e.g., to enhance the voltage output of the battery.Non-metals that may be used as doping agents in certain aspects include,but are not limited to: sulfur, iodine and the like.

In accordance with the various aspects of the present invention, thesystem of the present invention can be inside specific food products(e.g. a granola bar), with one of the data encoded and communicated bythe system being the caloric content of the food or other relevantdietary information, e.g. fiber sugar content, fat type and content etc.This may help people on a diet monitor their daily intakes, getincentives for staying on-diet, etc. Also, the system is co-ingestedwith food, using on-board sensing to measure food release into thestomach, e.g. fat content. Various aspects may include an instrumentedcup that detects when the system of the present invention has beendropped into the cup and whether the user or person took a drink(similar, for example, to the inhaler product described in PCTApplication Ser. No. PCT/US11/31986, filed Apr. 11, 2011, the entiredisclosure of which is incorporated herein by reference), and how muchthey drank. An advantage of this aspect of the present invention is thatit may be useful for people who take regular supplements in the form ofa powder or other, which is mixed with water before drinking.

In accordance with other aspects of the present invention, chemicalmarkers can incorporate certain marker species into the food (e.g. salt,low-or-high pH, protein, and lipid). When ingested, a marker species isreleased into stomach environment. With the sensing capability, thesystem of the present invention can detect chemical-binding receptors onthe surface or by coating on the system that reacts with achemically-active coating (e.g. a coating such as aspecific-ion-conducting glass membrane that allows only the desiredmarker species to penetrate). In various aspects, the ingestible deviceis co-ingested with the food, and may be used, among other things, tomeasure/detect the presence of the “marker species”. The system that isingestible and masticable can contain a detector capable of measuringendocanabinoids, as described for example, in the publication byDiPatrizio et al. entitled, “Endocannabinoid signal in the gut controlsdietary fat intake”, for example reference, the entire disclose of whichis incorporated herein by reference). When the signal is detected—e.g.,a sign that high fat food intake has occurred—the user or patient isinstructed via phone message or other communication to take aprescription (also RIS-enabled) to disrupt the endocannabinoid signal,thus reducing the craving for more high fat foods.

In accordance with another aspect of the present invention, the systemis detectable when the skirt is missing. In accordance with anotheraspect of the present invention, the system is safe to bite, for exampleby thinning the silicon. In accordance with another aspect of thepresent invention, several of the systems of the present invention areplaced in the food so that if some of the ingestible devices are damagedduring mastication there are still functional devices left. Thus, thesystems could be distributed throughout the food, so that the number ofsystems detected gives an indication of the quantity of food consumed.Additionally, another aspect of the present invention teaches that thesystem of the present invention can be surrounded with gummy materialand laminated between polymer layers that are soluble at low pH, but notin neutral pH (saliva). Furthermore, by reversing the coating, theopposite effect is achieved in accordance with another aspect of thepresent invention. First coat/laminate the system of the presentinvention with a pH sensitive polymer and then insert it inside small,gummy particles, e.g., gummy bites, to help survive in the mouth. Thus,the system of the present invention is inside a gummy-bear likeprotective layer, and may be reduced in size, such as skirt-less orflexible skirt. The protective layer may consist of multilayers or mayhave a density or solubility gradient such that the material nearest thesystem is only slowly soluble and likely to be swallowed due to slipperysurface, rounded shape and very small size. The system, according toanother aspect of the present invention, would have a circuitmodification that, in addition to probing the local impedance, has afeedback to postpone activation while the local impedance is high. Thisallows time for the remaining layer(s) to dissolve. The system isactivated or turns on as soon as liquid penetrates through, but cannotsend sufficient signal strength for detection, the high current andbattery layer depletion is postponed until the impedance dropssufficiently. Thus, the system according to this aspect of the presentinvention, for example, is put into pre-measured meal and snack types toread out what was consumed.

It is to be understood that this invention is not limited to particularaspects or aspects described, as such may vary. It is also to beunderstood that the terminology used herein is for the purpose ofdescribing particular aspects only, and is not intended to be limiting,since the scope of the present invention will be limited only by theappended claims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range, is encompassed within the invention. The upper and lowerlimits of these smaller ranges may independently be included in thesmaller ranges and are also encompassed within the invention, subject toany specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the invention.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present invention, representativeillustrative methods and materials are now described.

All publications and patents cited in this specification are hereinincorporated by reference as if each individual publication or patentwere specifically and individually indicated to be incorporated byreference and are incorporated herein by reference to disclose anddescribe the methods and/or materials in connection with which thepublications are cited. The citation of any publication is for itsdisclosure prior to the filing date and should not be construed as anadmission that the present invention is not entitled to antedate suchpublication by virtue of prior invention. Further, the dates ofpublication provided may be different from the actual publication dateswhich may need to be independently confirmed.

It is noted that, as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise. It is further noted that the claimsmay be drafted to exclude any optional element. As such, this statementis intended to serve as antecedent basis for use of such exclusiveterminology as “solely,” “only” and the like in connection with therecitation of claim elements, or use of a “negative” limitation.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual aspects described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalaspects without departing from the scope or spirit of the presentinvention. Any recited method can be carried out in the order of eventsrecited or in any other order which is logically possible.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity ofunderstanding, it is readily apparent to those of ordinary skill in theart in light of the teachings of this invention that certain changes andmodifications may be made thereto without departing from the spirit orscope of the appended claims.

Accordingly, the preceding merely illustrates the principles of theinvention. It will be appreciated that those skilled in the art will beable to devise various arrangements which, although not explicitlydescribed or shown herein, embody the principles of the invention andare included within its spirit and scope. Furthermore, all examples andconditional language recited herein are principally intended to aid thereader in understanding the principles of the invention and the conceptscontributed by the inventors to furthering the art, and are to beconstrued as being without limitation to such specifically recitedexamples and conditions. Moreover, all statements herein recitingprinciples, aspects, and aspects of the invention as well as specificexamples thereof, are intended to encompass both structural andfunctional equivalents thereof. Additionally, it is intended that suchequivalents include both currently known equivalents and equivalentsdeveloped in the future, i.e., any elements developed that perform thesame function, regardless of structure. The scope of the presentinvention, therefore, is not intended to be limited to the exemplaryaspects shown and described herein. Rather, the scope and spirit ofpresent invention is embodied by the appended claims.

What is claimed is:
 1. A signal producing product comprising: a firstcoating material; a second coating material; and a communication deviceat least partially surrounded by the first coating material, wherein thesecond coating material at least partially surrounds the communicationdevice and the first coating material, wherein the communication devicecomprises: a first material; a second material; and a circuitelectrically coupled to the first material and the second material andconfigured to control electrical conductance between the first materialand the second material to generate a remotely detectable signaltherebetween, wherein the circuit is configured to determine a localimpedance and to postpone activation of the communication device, toallow time for the first coating material to dissolve, while the localimpedance is at a level such that the detectable signal does not havesufficient signal strength for detection; wherein the first material andthe second material are configured to generate a voltage potential toprovide power to the communication device when the first material andthe second material are in contact with an electrically conductivefluid; and wherein the second coating material is configured towithstand mastication pressure to prevent activation of thecommunication device as a user chews the signal producing product; andwherein the first coating material is configured to dissolve in theuser's stomach.
 2. The signal producing product of claim 1, wherein atleast one of the first coating material or the second coating materialcomprises a chemically active coating, and wherein the chemically activecoating comprises a marker species.
 3. The signal producing product ofclaim 1, wherein the communication device is configured to communicateinformation to a detector associated with the user's body.
 4. The signalproducing product of claim 3, wherein the detector receives and decodesthe information communicated by the communication device.
 5. The signalproducing product of claim 1, wherein the first coating material isconfigured to dissolve when in contact with a physiological fluid. 6.The signal producing product of claim 1, wherein the communicationdevice is configured to communicate with a receiver secured to theuser's skin.
 7. The signal producing product of claim 1, furthercomprising a sensor in communication with and electrically connected tothe communication device.
 8. The signal producing product of claim 7,wherein the sensor is configured to detect a pH level of an environmentsurrounding the communication device and to send a signal to thecircuit.
 9. The signal producing product of claim 8, wherein the circuitvaries a rate of transfer of mass that produces an ionic transferbetween the first material and the second material to encode informationrelevant to the pH level in the ionic transfer.
 10. The signal producingproduct of claim 1, wherein the communication device further comprises asupport structure, wherein the first material is physically associatedwith the support structure and the second material is physicallyassociated with the support structure at a location different from thefirst material.
 11. The signal producing product of claim 10, whereinthe support structure comprises the circuit.
 12. The signal producingproduct of claim 11, wherein the communication device further comprisesa non-conductive membrane secured to the support structure, wherein thenon-conductive membrane is positioned relative to the first material andthe second material is configured to facilitate extension of anelectrical current path through the electrically conductive fluidbetween the first material and second material.
 13. The signal producingproduct of claim 1, wherein the communication device is a firstcommunication device, and wherein the signal producing product furthercomprises a second communication device.
 14. The signal producingproduct of claim 1, further comprising a digestible material.
 15. Thesignal producing product of claim 14, wherein the digestible materialcomprises a food material.
 16. The signal producing product of claim 15,wherein the communication device is configured to produce informationthat indicates that the food material has been consumed upon activationof the communication device.
 17. The signal producing product of claim15, further comprising a pharmaceutical product in an ingestible formand associated with the communication device and the food material, suchthat ingestion of the signal producing product by the user delivers thepharmaceutical product to the user.
 18. The signal producing product ofclaim 14, wherein the first coating material is positioned between thedigestible material and the communication device to isolate thedigestible material from the communication device.
 19. The signalproducing product of claim 14, wherein the digestible material comprisesa liquid.
 20. A signal producing product comprising: a digestiblematerial; a coating material; and a communication device associated withthe digestible material and at least partially surrounded by the coatingmaterial, wherein the communication device comprises: a first material;a second material; a circuit electrically coupled to the first materialand the second material and configured to control electrical conductancebetween the first material and the second material to generate aremotely detectable signal therebetween; wherein the first material andthe second material are configured to generate a voltage potential toprovide power to the communication device when the first material andthe second material are in contact with an electrically conductivefluid; and wherein the coating material is configured to withstandmastication pressure to prevent activation of the communication deviceas a user chews the signal producing product; and wherein the coatingmaterial is configured to dissolve in the user's stomach; and whereinthe communication device is a first communication device and the coatingmaterial is a first coating material, wherein the signal producingproduct further comprises a second communication device; and wherein thesecond communication device is at least partially surrounded by a secondcoating, wherein the second coating is configured to break as the userchews the signal producing product.
 21. A signal producing productcomprising: a digestible material; a coating material; and acommunication device associated with the digestible material and atleast partially surrounded by the coating material, wherein thecommunication device comprises: a first material; a second material; acircuit electrically coupled to the first material and the secondmaterial and configured to control electrical conductance between thefirst material and the second material to generate a remotely detectablesignal therebetween; wherein the first material and the second materialare configured to generate a voltage potential to provide power to thecommunication device when the first material and the second material arein contact with an electrically conductive fluid; and wherein thecoating material is configured to withstand mastication pressure toprevent activation of the communication device as a user chews thesignal producing product; and wherein the coating material is configuredto dissolve in the user's stomach; and wherein the communication deviceis a first communication device and the coating material is a firstcoating material, wherein the signal producing product further comprisesa second communication device; and wherein the second communicationdevice is configured to activate upon contact with the user's saliva.